This invention relates to a novel propellant composition and more particularly to a novel liquid monopropellant composition suitable for rendering underwater propulsion. In a further aspect, this invention relates to a method for obtaining underwater propulsion whereby the novel liquid monopropellant of this invention is combusted in the chamber of an underwater reaction motor.
Propellant compositions may be generally classed according to their physical state, whether solid, liquid, or slurry, a hybrid of solid and liquid. Within these broader definitions, propellant compositions may be typified as being multipropellant or monopropellant, depending on whether the fuel and oxidant are stored and maintained separately until the moment of combustion or are combined in a single composition. In general, liquid monopropellants are considered the favored class of propulsion means since they are easier to load, require only one tank for storage, one pump, one nozzle, one fuel line and one set of controls, and further because variable thrust control in the liquid propellant is generally easier to obtain. Heretofore, however, no wholly satisfactory liquid monopropellant composition has been provided for underwater utility in such critical operations as torpedo propulsion and the like. Consequently, the prior art has been forced to rely on such lesser desirable compositions as the solid monopropellants or the solid or liquid multipropellants. Solid propellants are unsatisfactory for torpedo propulsion for several reasons: first, due to possible variances in burning area resulting from uneven erosion and cracking, combustion of the solid propellant is of an unacceptably unsteady rate; second, since combustion of solid propellants generally result in the formation of a high percentage of non-condensible exhaust gases, underwater vehicles propelled by solid propellants are often characterized by severe wake formation in shallow waters; and finally, since both thrust and combustion in solid propellants are pressure dependent, propulsion of the underwater vehicle is highly sensitive to slight vehicle depth variations.
Liquid multipropellant systems are equally unsatisfactory for underwater propulsion principally since they require extensive ullage space and oxygen venting which preclude sealed cartridge loading, and require separate transfer and metering mechanisms for fuel and oxidant wherein high potential hazards of accidental mixing exists.